I don't like Naim preamps; too much things hanging on poor volume pot
Iron Pre is more neutral (JFet buffer being pretty much invisible, fed with more than decent shunt reg), also having more dynamics , due to fact of gain originating from xformer only- nice simple Signal Energy Preservation proven device
Spooky - meaning:
- even more neutral JFet buffer (shunt reg being exclusively one per channel),
-skipped Universal Signal Energy Antipreservation Device ( resistive volume attenuator),
- Autoformer at output doing both volume level selecting and gain , if asked for
so , don't ask me for NaimSchnaim and lookalikes**
**I'm not saying that anyone else is not having all rights to like most whatever he chose
Iron Pre is more neutral (JFet buffer being pretty much invisible, fed with more than decent shunt reg), also having more dynamics , due to fact of gain originating from xformer only- nice simple Signal Energy Preservation proven device
Spooky - meaning:
- even more neutral JFet buffer (shunt reg being exclusively one per channel),
-skipped Universal Signal Energy Antipreservation Device ( resistive volume attenuator),
- Autoformer at output doing both volume level selecting and gain , if asked for
so , don't ask me for NaimSchnaim and lookalikes**
**I'm not saying that anyone else is not having all rights to like most whatever he chose
Dear ZM,
I'm facing a dilemma.
I need a volume control between my DAC and my speaker amps.
The DAC is DIY, it features I/V resistors followed by a buffer and a transformer (that can handle a little DC). I use only balanced connections for now.
I was thinking of getting better transformers with volume control: Sowter 9335 TVC.
BUT, one day or another, I'll be getting a tuner, a CD player, etc... so wondering if the Iron Pumpkin could do the trick, understand being more versatile and a more effective investment, being able to attenuate and switch different sources.
What do you think?
I'm facing a dilemma.
I need a volume control between my DAC and my speaker amps.
The DAC is DIY, it features I/V resistors followed by a buffer and a transformer (that can handle a little DC). I use only balanced connections for now.
I was thinking of getting better transformers with volume control: Sowter 9335 TVC.
BUT, one day or another, I'll be getting a tuner, a CD player, etc... so wondering if the Iron Pumpkin could do the trick, understand being more versatile and a more effective investment, being able to attenuate and switch different sources.
What do you think?
well, you'll not find me modest there (even if I'm usually exemplar of Modesty 
)
You'll hardly find anything comparable on the market, considering sound quality and versatility of package
regarding sound quality alone, if overall invisibility of stage is the goal , Iron Pumpkin can stand its own against anything imaginable, regarding price tag
feel free to search and draw your own conclusions
)You'll hardly find anything comparable on the market, considering sound quality and versatility of package
regarding sound quality alone, if overall invisibility of stage is the goal , Iron Pumpkin can stand its own against anything imaginable, regarding price tag
feel free to search and draw your own conclusions
no, no DC allowed in Iron Pumpkin
it is designed to be DC coupled all through, and solving DC Offset problems - at source side - wasn't my job while constructing it
even if I did include small cap on input of buffer, first thing ppl would ask is - "can I remove that?"
so , considering 100K of Iron Pumpkin Rin, even 330nF as coupling cap on output of your DAC should be good to have proper phase at 20Hz (being calc. for 5Hz F3)
edit:
"few millivolts" .......... that can be many things ; practically, even stages with active servo are rarely ditto at 0mV level, so we always have some DC residual.... practically, we are not loosing a sleep if line level thingy is having few mV of fluctuation, but how much is allowable always depends of rest of signal chain
I'm sure that IP wouldn't be bothered wit +/-10mV at input (thinking solely of AVC behavior), and whatever gain setting of IP is, there is no DC gain
but, you must count is there DC gain in your output amp, or not .........
those are the reasons why I think that, say, 10mV is border value for line level stage DC offset ..... while 100mV at output of amp is peanut value
it is designed to be DC coupled all through, and solving DC Offset problems - at source side - wasn't my job while constructing it
even if I did include small cap on input of buffer, first thing ppl would ask is - "can I remove that?"
so , considering 100K of Iron Pumpkin Rin, even 330nF as coupling cap on output of your DAC should be good to have proper phase at 20Hz (being calc. for 5Hz F3)
edit:
"few millivolts" .......... that can be many things ; practically, even stages with active servo are rarely ditto at 0mV level, so we always have some DC residual.... practically, we are not loosing a sleep if line level thingy is having few mV of fluctuation, but how much is allowable always depends of rest of signal chain
I'm sure that IP wouldn't be bothered wit +/-10mV at input (thinking solely of AVC behavior), and whatever gain setting of IP is, there is no DC gain
but, you must count is there DC gain in your output amp, or not .........
those are the reasons why I think that, say, 10mV is border value for line level stage DC offset ..... while 100mV at output of amp is peanut value
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no reason
in fact, I did send one with two rotary switches extra, to connect to gain headers, so Chap could use them as separate gain controls, thus working as balance control
though, to my liking, having so disparate speaker position is too much of compromise; I'm not so HiEndish regard life, setups and everything, but when I invest money and time, then I can be sloppy and not-caring where I'm sitting and how ..... as a matter of choice, not necessity
in other words - make it perfect, then sit on one speaker , if you prefer
in fact, I did send one with two rotary switches extra, to connect to gain headers, so Chap could use them as separate gain controls, thus working as balance control
though, to my liking, having so disparate speaker position is too much of compromise; I'm not so HiEndish regard life, setups and everything, but when I invest money and time, then I can be sloppy and not-caring where I'm sitting and how ..... as a matter of choice, not necessity
in other words - make it perfect, then sit on one speaker , if you prefer
Finally I put the IP_SE_TL together. The TL is for Turtle-less. Frankly I was a little nervous for having a solder bridge somewhere. While powering up and setting voltage and offset I noticed how gentle it setled to stable values and took some measurements . In all gain contradictions I hooked the Pumpkin to F4. ZM, know the cricket behind the speaker. I heard it smile with a wicked twitch in the corner of its eye. My brain has normally a burnin for a couple of weeks but after 30 seconds I too got something twitching in my eye. Thank You, ZM!
With F4 and full throttle I got 80 dB in my sofa. I will set it up with F6 and Aleph J later if my smile fades I don’t think my speaker(105dB) has ever sounded so nice.
My wife is happy withe oak front so now I have to upgrade the other ones.
With F4 and full throttle I got 80 dB in my sofa. I will set it up with F6 and Aleph J later if my smile fades
I don’t think my speaker(105dB) has ever sounded so nice. My wife is happy withe oak front so now I have to upgrade the other ones.
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high Rout enabling xtalk
remedy is disabling grounding of unused inputs and parallel connection of "normally off" relay contacts
see attached picture
if you remove mosfet htsnks, you can find adequate L bracket to mount your attenuator in between channel pcbs, using extending shaft and coupler, thus shorting connection wires drastically
disassemble old bad pot with 6mm shaft, use its face part and you have nice sleeve for extending shaft , for front plate
one thing - I did found those pre-made ebay attenuators tricky - they can start cracking and loosing contact relatively soon
I'm using sorta same switches for controlling Turtle relays, but each one is disassembled and well greased before putting on pcb, which is logically not possible with already assembled attenuators
good to know, if happens, you're not first
remedy is disabling grounding of unused inputs and parallel connection of "normally off" relay contacts
see attached picture
if you remove mosfet htsnks, you can find adequate L bracket to mount your attenuator in between channel pcbs, using extending shaft and coupler, thus shorting connection wires drastically
disassemble old bad pot with 6mm shaft, use its face part and you have nice sleeve for extending shaft , for front plate
one thing - I did found those pre-made ebay attenuators tricky - they can start cracking and loosing contact relatively soon
I'm using sorta same switches for controlling Turtle relays, but each one is disassembled and well greased before putting on pcb, which is logically not possible with already assembled attenuators
good to know, if happens, you're not first
Attachments
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